In one example conventional process, a photoresist layer is applied on a substrate and patterned so that some areas of the substrate are exposed. The exposed areas are then implanted with dopants. However, the implantation process may chemically change an outer portion of the photoresist layer so that the outer portion includes tough polymers with inter-molecular bonds. The chemically changed outer portion of the photoresist layer may make the photoresist layer more difficult to remove using conventional techniques.